(1) A grouping of messages that share certain characteristics. A message domain has an associated parser that interprets messages that are received and generated by a broker. WebSphere Business Integration Message Broker supports messages in the BLOB domain, JMS domain, MRM domain, and XML domain. User-defined parsers can be used to support messages that do not conform to the supported domains.
(2) Major component of CICS. It is a repository for CICS messages and it handles the sending of messages to transient data destinations or to the console. It also provides an interface for returning the text of a message to the caller.